//**********************************
// Compiler
// 21/09/2012 - 21/09/2012
//**********************************
// Christophe Riccio
// ogl-samples@g-truc.net
//**********************************
// G-Truc Creation
// www.g-truc.net
//**********************************

#include "compiler.hpp"

#include <glm/gtc/random.hpp>

#include <string>
#include <sstream>
#include <fstream>
#include <cstdarg>

std::string getDataDirectory();

compiler::commandline::commandline(std::string const & Filename, std::string const & Arguments) :
	Profile("core"),
	Version(-1)
{
	std::size_t PathOffset = Filename.find_last_of("/");
	std::string FilePath = Filename.substr(0, PathOffset + 1);

	this->Includes.push_back(FilePath);
	this->parseArguments(Arguments);
}

void compiler::commandline::parseArguments(std::string const & Arguments)
{
	std::stringstream Stream(Arguments);
	std::string Param;

	while(!Stream.eof())
	{
		Stream >> Param;

		std::size_t FoundDefine = Param.find("-D");
		std::size_t FoundInclude = Param.find("-I");

		if(FoundDefine != std::string::npos)
			this->Defines.push_back(Param.substr(2, Param.size() - 2));
		else if(FoundInclude != std::string::npos)
			this->Includes.push_back(getDataDirectory() + Param.substr(2, Param.size() - 2));
		else if(Param == "--define")
		{
			std::string Define;
			Stream >> Define;
			this->Defines.push_back(Define);
		}
		else if((Param == "--version") || (Param == "-v"))
			Stream >> Version;
		else if((Param == "--profile") || (Param == "-p"))
			Stream >> Profile;
		else if (Param == "--include")
		{
			std::string Include;
			Stream >> Include;
			this->Includes.push_back(getDataDirectory() + Include);
		}
/*
		else 
		{
			std::stringstream err;
			err << "unknown parameter type: \"" << Param << "\"";
			glDebugMessageInsertARB(
				GL_DEBUG_SOURCE_APPLICATION_ARB, GL_DEBUG_TYPE_OTHER_ARB, 1, GL_DEBUG_SEVERITY_LOW_ARB, 
				-1, std::string(std::string("unknown parameter type: \"") << Param << std::string("\"")).c_str());
		}
		if(!Stream) 
		{
			glDebugMessageInsertARB(
				GL_DEBUG_SOURCE_APPLICATION_ARB, GL_DEBUG_TYPE_OTHER_ARB, 1, GL_DEBUG_SEVERITY_LOW_ARB, 
				-1, std::string(std::string("error parsing parameter: \"") << Param << std::string("\"")).c_str());
		}
*/
	}
}

std::string compiler::commandline::getDefines() const
{
	std::string Result;
	for(std::size_t i = 0; i < this->Defines.size(); ++i)
		Result += std::string("#define ") + this->Defines[i] + std::string("\n");
	return Result;
}

// compiler::parser

std::string compiler::parser::operator()(commandline const & CommandLine, std::string const & Filename) const
{
	std::string Source = load_file(Filename);
	assert(!Source.empty());

	std::stringstream Stream;
	Stream << Source;
	std::string Line, Text;

	// Handle command line version and profile arguments
	if(CommandLine.getVersion() != -1)
		Text += format("#version %d %s\n", CommandLine.getVersion(), CommandLine.getProfile().c_str());

	// Handle command line defines
	Text += CommandLine.getDefines();

	while(std::getline(Stream, Line))
	{
		std::size_t Offset = 0;

		// Version
		Offset = Line.find("#version");
		if(Offset != std::string::npos)
		{
			std::size_t CommentOffset = Line.find("//");
			if(CommentOffset != std::string::npos && CommentOffset < Offset)
				continue;

			// Reorder so that the #version line is always the first of a shader text
			if(CommandLine.getVersion() == -1)
				Text = Line + std::string("\n") + Text;
			// else skip is version is only mentionned
			continue;
		}

		// Include
		Offset = Line.find("#include");
		if(Offset != std::string::npos)
		{
			std::size_t CommentOffset = Line.find("//");
			if(CommentOffset != std::string::npos && CommentOffset < Offset)
				continue;

			std::string Include = parseInclude(Line, Offset);

			std::vector<std::string> Includes = CommandLine.getIncludes();

			for(std::size_t i = 0; i < Includes.size(); ++i)
			{
				std::string PathName = Includes[i] + Include;
				std::string IncludeSource = load_file(PathName);
				if (!IncludeSource.empty())
				{
					Text += IncludeSource;
					break;
				}
			}

			continue;
		} 

		Text += Line + "\n";
	}

	//Text += glf::format("\nconst float G_TRUC_GNI = %f;\n", glm::linearRand(0.0f, 1.0f));

	return Text;
}

std::string compiler::parser::parseInclude(std::string const & Line, std::size_t const & Offset) const
{
	std::string Result;

	std::string::size_type IncludeFirstQuote = Line.find("\"", Offset);
	std::string::size_type IncludeSecondQuote = Line.find("\"", IncludeFirstQuote + 1);

	return Line.substr(IncludeFirstQuote + 1, IncludeSecondQuote - IncludeFirstQuote - 1);
}

// compiler
compiler::~compiler()
{
	this->clear();
}

GLuint compiler::create(GLenum Type, std::string const & Filename, std::string const & Arguments)
{
	assert(!Filename.empty());
	
	commandline CommandLine(Filename, Arguments);

	std::string PreprocessedSource = parser()(CommandLine, Filename);
	assert(!PreprocessedSource.empty());
	char const* PreprocessedSourcePointer = PreprocessedSource.c_str();

	fprintf(stdout, "%s\n", PreprocessedSource.c_str());

	GLuint Name = glCreateShader(Type);
	glShaderSource(Name, 1, &PreprocessedSourcePointer, NULL);
	glCompileShader(Name);

	std::pair<files_map::iterator, bool> ResultFiles = this->ShaderFiles.insert(std::make_pair(Name, Filename));
	assert(ResultFiles.second);
	std::pair<names_map::iterator, bool> ResultNames = this->ShaderNames.insert(std::make_pair(Filename, Name));
	assert(ResultNames.second);
	std::pair<names_map::iterator, bool> ResultChecks = this->PendingChecks.insert(std::make_pair(Filename, Name));
	assert(ResultChecks.second);

	return Name;
}

bool compiler::destroy(GLuint const & Name)
{
	files_map::iterator NameIterator = this->ShaderFiles.find(Name);
	if(NameIterator == this->ShaderFiles.end())
		return false; // Shader name not found
	std::string File = NameIterator->second;
	this->ShaderFiles.erase(NameIterator);

	// Remove from the pending checks list
	names_map::iterator PendingIterator = this->PendingChecks.find(File);
	if(PendingIterator != this->PendingChecks.end())
		this->PendingChecks.erase(PendingIterator);

	// Remove from the pending checks list
	names_map::iterator FileIterator = this->ShaderNames.find(File);
	assert(FileIterator != this->ShaderNames.end());
	this->ShaderNames.erase(FileIterator);

	return true;
}

bool compiler::validate_program(GLuint ProgramName) const
{
	if(!ProgramName)
		return false;

	glValidateProgram(ProgramName);
	GLint Result = GL_FALSE;
	glGetProgramiv(ProgramName, GL_VALIDATE_STATUS, &Result);

	if(Result == GL_TRUE)
		return true;

	fprintf(stdout, "Validate program\n");
	int InfoLogLength;
	glGetProgramiv(ProgramName, GL_INFO_LOG_LENGTH, &InfoLogLength);
	if(InfoLogLength > 0)
	{
		std::vector<char> Buffer(InfoLogLength);
		glGetProgramInfoLog(ProgramName, InfoLogLength, NULL, &Buffer[0]);
		fprintf(stdout, "%s\n", &Buffer[0]);
	}

	return Result == GL_TRUE;
}

bool compiler::check_program(GLuint ProgramName) const
{
	if(!ProgramName)
		return false;

	GLint Result = GL_FALSE;
	glGetProgramiv(ProgramName, GL_LINK_STATUS, &Result);

	if(Result == GL_TRUE)
		return true;

	//fprintf(stdout, "Linking program\n");
	int InfoLogLength;
	glGetProgramiv(ProgramName, GL_INFO_LOG_LENGTH, &InfoLogLength);
	if(InfoLogLength > 0)
	{
		std::vector<char> Buffer(glm::max(InfoLogLength, int(1)));
		glGetProgramInfoLog(ProgramName, InfoLogLength, NULL, &Buffer[0]);
		fprintf(stdout, "%s\n", &Buffer[0]);
	}

	return Result == GL_TRUE;
}

// TODO Interaction with KHR_debug
bool compiler::check()
{
	bool Success(true);

	for
	(
		names_map::iterator ShaderIterator = PendingChecks.begin();
		ShaderIterator != PendingChecks.end();
		++ShaderIterator
	)
	{
		GLuint ShaderName = ShaderIterator->second;
		GLint Result = GL_FALSE;
		glGetShaderiv(ShaderName, GL_COMPILE_STATUS, &Result);

		if(Result == GL_TRUE)
			continue;

		int InfoLogLength;
		glGetShaderiv(ShaderName, GL_INFO_LOG_LENGTH, &InfoLogLength);
		if(InfoLogLength > 0)
		{
			std::vector<char> Buffer(InfoLogLength);
			glGetShaderInfoLog(ShaderName, InfoLogLength, NULL, &Buffer[0]);
			fprintf(stdout, "%s\n", &Buffer[0]);
		}

		Success = Success && Result == GL_TRUE;
	}
	
	return Success; 
}

void compiler::clear()
{
	for(
		names_map::iterator ShaderNameIterator = this->ShaderNames.begin(); 
		ShaderNameIterator != this->ShaderNames.end(); 
		++ShaderNameIterator)
		glDeleteShader(ShaderNameIterator->second);

	this->ShaderNames.clear();
	this->ShaderFiles.clear();
	this->PendingChecks.clear();
}

std::string load_file(std::string const & Filename)
{
	std::string Result;
		
	std::ifstream Stream(Filename.c_str());
	if(!Stream.is_open())
		return Result;

	Stream.seekg(0, std::ios::end);
	Result.reserve(Stream.tellg());
	Stream.seekg(0, std::ios::beg);
		
	Result.assign(
		(std::istreambuf_iterator<char>(Stream)),
		std::istreambuf_iterator<char>());

	return Result;
}

bool load_binary
(
	std::string const & Filename,
	GLenum & Format,
	std::vector<glm::uint8> & Data,
	GLint & Size
)
{
	FILE* File = fopen(Filename.c_str(), "rb");

	if(File)
	{
		fread(&Format, sizeof(GLenum), 1, File);
		fread(&Size, sizeof(Size), 1, File);
		if(Size > 0)
		{
			Data.resize(Size);
			fread(&Data[0], Size, 1, File);
			return true;
		}
		fclose(File);
	}
	return false;
}
	
bool save_binary
(
	std::string const & Filename,
	GLenum const & Format,
	std::vector<glm::uint8> const & Data,
	GLint const & Size
)
{
	FILE* File = fopen(Filename.c_str(), "wb");

	if(File)
	{
		fwrite(&Format, sizeof(GLenum), 1, File);
		fwrite(&Size, sizeof(Size), 1, File);
		fwrite(&Data[0], Size, 1, File);
		fclose(File);
		return true;
	}
	return false;
}
